It is possible to manufacture high-purity polycrystalline silicon by the hydrogen reduction reaction of trichlorosilane shown in the following reaction formula (1) and the thermal decomposition reaction of trichlorosilane shown in the following reaction formula (2) while using, for example, trichlorosilane (SiHCl3: abbreviated as TCS), silicon tetrachloride (SiCl4: abbreviated as STC) and hydrogen as raw materials.SiHCl3+H2→Si+3HCl  (1)4SiHCl3→Si+3SiCl4+2H2  (2)
Trichlorosilane, which is a raw material of the above-mentioned manufacturing method, is produced by distilling and purifying crude trichlorosilane obtained by the reaction hydrogen chloride with metallurgical grade silicon. Further, it may be possible to produce trichlorosilane by a hydrogenation conversion reaction shown in the following reaction formula (3) while using silicon tetrachloride, which is recovered from an discharged gas of a polycrystalline silicon producing reaction through distillation and separation, as a raw material.SiCl4+H2→SiHCl3+HCl  (3)
For example, a conversion reaction apparatus (conversion furnace) disclosed in Patent Document 1 is known as an apparatus for manufacturing trichlorosilane. In the conversion reaction apparatus, a reaction chamber surrounded by heating elements includes double chambers (an inner chamber and an outer chamber) formed of two pipes that are concentrically arranged, a heat exchanger is provided at a lower portion of the reaction chamber, and a raw material gas supplying tube through which hydrogen and silicon tetrachloride are supplied and a discharge tube through which a reaction product gas is discharged from the reaction chamber are connected to the reaction chamber through the heat exchanger. In the heat exchanger, a feed gas supplied to the reaction chamber is preheated by heat transferred from a reaction product gas that is discharged from the reaction chamber, and the reaction product gas to be discharged is cooled.
Further, for example, Patent Document 2 proposes an apparatus. The apparatus includes a reaction chamber for obtaining a reaction product gas containing trichlorosilane and hydrogen chloride by introducing silicon tetrachloride and hydrogen to the reaction chamber and performing the conversion reaction of the silicon tetrachloride and hydrogen at a temperature of 600 to 1200° C., and a cooling device that rapidly cools the reaction product gas discharged from the reaction chamber, for example, at a cooling rate that makes the reaction product gas reach a temperature of 300° C. or lower within one second.
[Patent Document 1] Japanese Patent Publication No. 3781439
[Patent Document 2] Japanese Examined Patent Application Second Publication No. S57-38524